Potentially transmissible human papillomavirus DNA has been identified in human blood cells suggesting that the virus, traditionally thought to be sexually transmitted, could also be spread through blood products. Researchers from the National Institutes of Health report their findings in the November 2005 issue of the Journal of Clinical Microbiology.

Human papillomavirus (HPV) is most commonly recognized as a sexually transmitted disease that can cause genital warts as well as cervical cancer. It had been widely accepted that HPVs could not be disseminated through blood. However, the successful experimental transmission of bovine papillomavirus through blood several years ago suggested that might not be the case.

In the study researchers examined HPV DNA in banked, frozen blood cells from pediatric HIV patients and fresh blood cells from healthy donors. Results showed that eight HIV patient samples (seven of which acquired HIV through blood transfusions) and three healthy donor samples were positive for two subgroups of the HPV type 16 genome and that the DNA could exist in a transmissible form.

"Peripheral blood mononuclear cells (PBMCs) might serve as a source of HPV in the infection of epithelial cells and contribute to their nonsexual spread," say the researchers. "However, additional work is needed to confirm this as a possible mode of HPV transmission."